<template>
    <div>
       <router-link
       tag="div"
       to="/"
       class="header-abs"
       v-show="showAbs"
       >
           <div class="iconfont header-abs-back">&#xec73;</div>
       </router-link>
       <div
       class="header-fixed"
       v-show="!showAbs"
       :style="opacityStyle"
       >
           <router-link to="/">
                <div class="iconfont header-fixed-back">&#xec73;</div>
           </router-link>
           景点详情
       </div>
    </div>
</template>
<script>

export default {
  name: 'DetailHeader',
  data () {
    return {
      showAbs: true,
      opacityStyle: {
        opacity: 0
      }
    }
  },
  methods: {
    handleScroll () {
      const top = document.documentElement.scrollTop
      if (top > 60) {
        let opacity = top / 140
        opacity = opacity > 1 ? 1 : opacity
        this.opacityStyle = { opacity }
        this.showAbs = false
      } else {
        this.showAbs = true
      }
    }
  },
  activated () {
    window.addEventListener('scroll', this.handleScroll)
  },
  deactivated () {
    window.removeEventListener('scroll', this.handleScroll)
  }

}
</script>
<style lang="stylus" scoped>
@import '~styles/varibles.styl'
    .header-abs
        position absolute
        left .2rem
        top .2rem
        width .8rem
        height .8rem
        line-height .8rem
        text-align center
        border-radius .4rem
        background: rgba(0,0,0, .8)
        .header-abs-back
            color #fff
            font-size .4rem
    .header-fixed
        z-index 2
        position fixed
        left:0
        top:0
        right 0
        height:$headerHeight
        line-height:$headerHeight
        text-align:center
        color:#fff
        background:$bgColor
        font-size:.32rem
        .header-fixed-back
            position:absolute
            width:.64rem
            left:0
            top:0
            text-align:center
            font-size:.4rem
            color:#fff
</style>
